scholarly journals Track-Density Ratio Mapping With Fiber Types in the Cerebral Cortex Using Diffusion-Weighted MRI

2021 ◽  
Vol 15 ◽  
Author(s):  
Sang-Han Choi ◽  
Gangwon Jeong ◽  
Young-Eun Hwang ◽  
Yong-Bo Kim ◽  
Haigun Lee ◽  
...  
Keyword(s):  
Cortical Area ◽  
Density Ratio ◽  
Nerve Fibers ◽  
Track Density ◽  
Fiber Types ◽  
Diffusion Weighted ◽  
Human Connectome Project ◽  
Association Fibers ◽  
Tractography Data ◽  
The Brain

The nerve fibers are divided into three categories: projection, commissural, and association fibers. This study demonstrated a novel cortical mapping method based on these three fiber categories using MR tractography data. The MR fiber-track data were extracted using the diffusion-weighted 3T-MRI data from 19 individuals’ Human Connectome Project dataset. Anatomical MR images in each dataset were parcellated using FreeSurfer software and Brainnetome atlas. The 5 million extracted tracks per subject by MRtrix software were classified based on the basic cortical structure (cortical area in the left and right hemisphere, subcortical area), after the tracks validation procedure. The number of terminals for each categorized track per unit-sized cortical area (1 mm3) was defined as the track-density in that cortical area. Track-density ratio mapping with fiber types was achieved by mapping the density-dependent color intensity for each categorized tracks with a different primary color. The mapping results showed a highly localized, unique density ratio map determined by fiber types. Furthermore, the quantitative group data analysis based on the parcellation information revealed that the majority of nerve fibers in the brain are association fibers, particularly in temporal, inferior parietal, and occipital lobes, while the projection and commissural fibers were mainly located in the superior part of the brain. Hemispheric asymmetries in the fiber density were also observed, such as long association fiber in the Broca’s and Wernicke’s areas. We believe this new dimensional brain mapping information allows us to further understand brain anatomy, function.

Individual Uniqueness in the Neonatal Functional Connectome

2021 ◽  
Author(s):  
Qiushi Wang ◽  
Yuehua Xu ◽  
Tengda Zhao ◽  
Zhilei Xu ◽  
Yong He ◽  
...  
Keyword(s):  
Individual Differences ◽  
Individual Identification ◽  
Imaging Data ◽  
Functional Connectome ◽  
Middle Range ◽  
Human Connectome Project ◽  
The Individual ◽  
And Behavior ◽  
Identification Analysis ◽  
The Brain

Abstract The functional connectome is highly distinctive in adults and adolescents, underlying individual differences in cognition and behavior. However, it remains unknown whether the individual uniqueness of the functional connectome is present in neonates, who are far from mature. Here, we utilized the multiband resting-state functional magnetic resonance imaging data of 40 healthy neonates from the Developing Human Connectome Project and a split-half analysis approach to characterize the uniqueness of the functional connectome in the neonatal brain. Through functional connectome-based individual identification analysis, we found that all the neonates were correctly identified, with the most discriminative regions predominantly confined to the higher-order cortices (e.g., prefrontal and parietal regions). The connectivities with the highest contributions to individual uniqueness were primarily located between different functional systems, and the short- (0–30 mm) and middle-range (30–60 mm) connectivities were more distinctive than the long-range (>60 mm) connectivities. Interestingly, we found that functional data with a scanning length longer than 3.5 min were able to capture the individual uniqueness in the functional connectome. Our results highlight that individual uniqueness is present in the functional connectome of neonates and provide insights into the brain mechanisms underlying individual differences in cognition and behavior later in life.

HISTOLOGY AND HISTOCHEMISTRY OF THE PINEAL ORGAN IN THE SOCKEYE SALMON, ONCORHYNCHUS NERKA WALBAUM

1967 ◽  
Vol 45 (1) ◽  
pp. 117-126 ◽  
Author(s):  
M. A. Hafeez ◽  
P. Ford
Keyword(s):  
Sockeye Salmon ◽  
Pineal Organ ◽  
Subcommissural Organ ◽  
Sensory Nerve ◽  
Nerve Fibers ◽  
Supporting Cells ◽  
Dependent Behavior ◽  
Aldehyde Fuchsin ◽  
Pineal Nerve ◽  
The Brain

The morphohistology and some histochemical aspects of the pineal organ in the sockeye salmon were studied. The distal part of the organ lies in a pineal fossa in the cranial roof. Photosensory cells and two kinds of ependymal supporting cells are present throughout its epithelium, which is entirely devoid of either melanin or lipofuchsin. Besides sensory nerve fibers, efferent end-loops are present on the photosensory as well as the supporting cells. The dorsal pineal nerve tract probably contains both sensory and efferent fibers. The apocrine secretion of sensory as well as some supporting cells is probably associated with either the maintenance of a constant chemical composition of the cerebrospinal fluid or with supply of certain chemical substances to the brain tissue. The secretion in the pineal and the subcommissural organ consists of glycogen, mucopolysaccharides, mucoproteins, and aldehyde fuchsin positive granules.It is proposed that the pineal organ is photosensory as well as secretory and that its photosensitivity might be of some significance in the light-dependent behavior of this species in terms of intensity detection.

Analysis of Changes in Signal Intensity of Choroid Plexus in MRI Using FLAIR-DW-EPI Pulse Sequence

2020 ◽  
Vol 3 (1) ◽  
pp. 9-15
Author(s):  
Jingyu Kim ◽  
◽  
Sang-Jin Im ◽  
Keyword(s):  
Choroid Plexus ◽  
Signal Intensity ◽  
Pulse Sequence ◽  
Signal Strength ◽  
Brain Parenchyma ◽  
Weighted Image ◽  
Diffusion Weighted ◽  
Water Signal ◽  
The Brain ◽  
Functional Problems

In this study, the signal intensity of choroid plexus, which is producing cerebrospinal fluid, is analyzed according to the FLAIR diffusion-weighted imaging technique. In the T2*-DW-EPI diffusion-weighted image, the FLAIR-DW-EPI technique, which suppressed the water signal, was additionally examined for subjects with high choroid plexus signals and compared and analyzed the signal intensity. As a result of the experiment, it was confirmed that the FLAIR-DW-EPI technique showed a signal strength equal to or lower than that of the brain parenchyma, and there was a difference in signal strength between the two techniques. As a result of this study, if the choroidal plexus signal is high in the T2 * -DW-EPI diffusionweighted image, additional examination of the FLAIR-DW-EPI technique is thought to be useful in distinguishing functional problems of the choroid plexus. In conclusion, if the choroidal plexus signal is high on the T2*-DW-EPI diffuse weighted image, it is thought that further examination of the FLAIR-DW-EPI technique will be useful in distinguishing functional problems of the choroidal plexus.

Diffusion-Weighted Imaging of the Brain in Preterm Infants With Focal and Diffuse White Matter Abnormality

PEDIATRICS ◽  
2003 ◽  
Vol 112 (1) ◽  
pp. 1-7 ◽  
Author(s):  
S. J. Counsell ◽  
J. M. Allsop ◽  
M. C. Harrison ◽  
D. J. Larkman ◽  
N. L. Kennea ◽  
...  
Keyword(s):  
White Matter ◽  
Preterm Infants ◽  
Diffusion Weighted Imaging ◽  
White Matter Abnormality ◽  
Diffuse White Matter ◽  
Diffusion Weighted ◽  
The Brain

scholarly journals Anatomical Study of Intrahemispheric Association Fibers in the Brains of Capuchin Monkeys (Sapajussp.)

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Kellen Christina Malheiros Borges ◽  
Hisao Nishijo ◽  
Tales Alexandre Aversi-Ferreira ◽  
Jussara Rocha Ferreira ◽  
Leonardo Ferreira Caixeta
Keyword(s):  
Nonhuman Primates ◽  
Evolutionary Process ◽  
Anatomical Study ◽  
Lateral View ◽  
Superior Longitudinal Fasciculus ◽  
Cognitive Behaviors ◽  
Behavioral Studies ◽  
Inferior Longitudinal Fasciculus ◽  
Association Fibers ◽  
The Brain

Previous studies suggest that the complexity of fiber connections in the brain plays a key role in the evolutionary process of the primate brain and behaviors. The patterns of brain fiber systems have been studied in detail in many nonhuman primates, but not inSapajussp. Behavioral studies indicated thatSapajussp. (bearded capuchins) show highly cognitive behaviors such as tool use comparable to those in other nonhuman primates. To compare the brain fiber systems in capuchins with those in other nonhuman primates and humans, the intrahemispheric fibers systems in 24 cerebral hemispheres ofSapajuswere dissected by a freezing-thawing procedure. Dissection of the hemispheres in lateral view indicated short arcuate fibers, uncinate fasciculus, and inferior longitudinal fasciculus, while that in a medial view indicated short arcuate fibers, the cingulum united with the superior longitudinal fasciculus, and inferior longitudinal fasciculus. The results showed that the fiber systems inSapajusare comparable to those in rhesus and humans, except for a lack of independent superior longitudinal fasciculus and cingulum inSapajus.

Nondestructive imaging of the internal microstructure of vessels and nerve fibers in rat spinal cord using phase-contrast synchrotron radiation microtomography

2017 ◽  
Vol 24 (2) ◽  
pp. 482-489 ◽  
Author(s):  
Jianzhong Hu ◽  
Ping Li ◽  
Xianzhen Yin ◽  
Tianding Wu ◽  
Yong Cao ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Synchrotron Radiation ◽  
Phase Contrast ◽  
Three Dimensional ◽  
Nerve Fibers ◽  
The Body ◽  
Rat Spinal Cord ◽  
Nondestructive Imaging ◽  
Synchrotron Radiation Microtomography ◽  
The Brain

The spinal cord is the primary neurological link between the brain and other parts of the body, but unlike those of the brain, advances in spinal cord imaging have been challenged by the more complicated and inhomogeneous anatomy of the spine. Fortunately with the advancement of high technology, phase-contrast synchrotron radiation microtomography has become widespread in scientific research because of its ability to generate high-quality and high-resolution images. In this study, this method has been employed for nondestructive imaging of the internal microstructure of rat spinal cord. Furthermore, digital virtual slices based on phase-contrast synchrotron radiation were compared with conventional histological sections. The three-dimensional internal microstructure of the intramedullary arteries and nerve fibers was vividly detected within the same spinal cord specimen without the application of a stain or contrast agent or sectioning. With the aid of image post-processing, an optimization of vessel and nerve fiber images was obtained. The findings indicated that phase-contrast synchrotron radiation microtomography is unique in the field of three-dimensional imaging and sets novel standards for pathophysiological investigations in various neurovascular diseases.

scholarly journals Scatterometry Measurements With Scattered Light Imaging Enable New Insights Into the Nerve Fiber Architecture of the Brain

2021 ◽  
Vol 15 ◽  
Author(s):  
Miriam Menzel ◽  
Marouan Ritzkowski ◽  
Jan A. Reuter ◽  
David Gräßel ◽  
Katrin Amunts ◽  
...  
Keyword(s):  
Human Brain ◽  
Nerve Fiber ◽  
Brain Tissue ◽  
Scattered Light ◽  
Polar Angle ◽  
Nerve Fibers ◽  
Fiber Architecture ◽  
Whole Brain ◽  
Tissue Samples ◽  
The Brain

The correct reconstruction of individual (crossing) nerve fibers is a prerequisite when constructing a detailed network model of the brain. The recently developed technique Scattered Light Imaging (SLI) allows the reconstruction of crossing nerve fiber pathways in whole brain tissue samples with micrometer resolution: the individual fiber orientations are determined by illuminating unstained histological brain sections from different directions, measuring the transmitted scattered light under normal incidence, and studying the light intensity profiles of each pixel in the resulting image series. So far, SLI measurements were performed with a fixed polar angle of illumination and a small number of illumination directions, providing only an estimate of the nerve fiber directions and limited information about the underlying tissue structure. Here, we use a display with individually controllable light-emitting diodes to measure the full distribution of scattered light behind the sample (scattering pattern) for each image pixel at once, enabling scatterometry measurements of whole brain tissue samples. We compare our results to coherent Fourier scatterometry (raster-scanning the sample with a non-focused laser beam) and previous SLI measurements with fixed polar angle of illumination, using sections from a vervet monkey brain and human optic tracts. Finally, we present SLI scatterometry measurements of a human brain section with 3 μm in-plane resolution, demonstrating that the technique is a powerful approach to gain new insights into the nerve fiber architecture of the human brain.

scholarly journals The Distribution of Skull Score and Skull Density Ratio in Tremor Patients for MR-Guided Focused Ultrasound Thalamotomy

2021 ◽  
Vol 15 ◽  
Author(s):  
Kevin Wen-Kai Tsai ◽  
Jui-Cheng Chen ◽  
Hui-Chin Lai ◽  
Wei-Chieh Chang ◽  
Takaomi Taira ◽  
...  
Keyword(s):  
Trabecular Bone ◽  
Cortical Bone ◽  
Focused Ultrasound ◽  
Density Ratio ◽  
Ct Images ◽  
Image Feature ◽  
Cumulative Distribution ◽  
Invasive Surgical Approach ◽  
Highly Correlated ◽  
The Brain

ObjectiveMagnetic resonance-guided focused ultrasound (MRgFUS) is a minimum-invasive surgical approach to non-incisionally cause the thermos-coagulation inside the human brain. The skull score (SS) has already been approved as one of the most dominant factors related to a successful MRgFUS treatment. In this study, we first reveal the SS distribution of the tremor patients, and correlate the SS with the image feature from customized skull density ratio (cSDR). This correlation might give a direction to future clinical studies for improving the SS.MethodsTwo hundred and forty-six patients received a computed tomography (CT) scan of the brain, and a bone-enhanced filter was applied and reconstructed to a high spatial resolution CT images. The SS of all patients would be estimated by the MRgFUS system after importing the reconstructed CT images into the MRgFUS system. The histogram and the cumulative distribution of the SS from all the patients were calculated to show the percentage of the patients whose SS lower than 0.3 and 0.4. The same CT images of all patients were utilized to calculated the cSDR by first segmented the trabecular bone and the cortical bone from the CT images and divided the average trabecular bone intensity (aTBI) by the average cortical bone intensity (aCBI). The Pearson’s correlations between the SS and the cSDR, aTBI, and the aCBI were calculated, respectively.ResultsThere were 19.19 and 50% of the patient who had the SS lower than the empirical threshold 0.3 and 0.4, respectively. The Pearson’s correlation between the SS and the cSDR, aCBI, and the aTBI were R = 0.8145, 0.5723, and 0.8842.ConclusionHalf of the patients were eligible for the MRgFUS thalamotomy based on the SS, and nearly 20% of patients were empirically difficult to achieve a therapeutic temperature during MRgFUS. The SS and our cSDR are highly correlated, and the SS had a higher correlation with aTBI than with aCBI. This is the first report to explicitly reveal the SS population and indicate a potential way to increase the chance to achieve a therapeutic temperature for those who originally have low SS.

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